U.S. patent application number 10/514305 was filed with the patent office on 2005-10-06 for low-cost ring blade for rotary knives.
Invention is credited to Rapp, Geoffrey D.
Application Number | 20050217119 10/514305 |
Document ID | / |
Family ID | 31978674 |
Filed Date | 2005-10-06 |
United States Patent
Application |
20050217119 |
Kind Code |
A1 |
Rapp, Geoffrey D |
October 6, 2005 |
Low-cost ring blade for rotary knives
Abstract
A ring blade (18) for use with a rotary knife (10) includes a
first member that forms an annular blade member (90) having an
annular cutting edge (96) for cutting into material with which it
is brought into contact. A second member (92) is fixed to the
annular blade member to provide a drive surface by which the ring
blade is rotated. In one embodiment the blade member is machined.
In another embodiment the blade member is cold formed from a thin
sheet of hardenable steel.
Inventors: |
Rapp, Geoffrey D; (Westlake,
OH) |
Correspondence
Address: |
Watts Hoffmann Fisher & Heinke Co
1100 Superior Avenue East
Suite 1750
Cleveland
OH
44114-2518
US
|
Family ID: |
31978674 |
Appl. No.: |
10/514305 |
Filed: |
November 12, 2004 |
PCT Filed: |
August 22, 2003 |
PCT NO: |
PCT/US03/26461 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60408769 |
Sep 6, 2002 |
|
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Current U.S.
Class: |
30/276 ;
452/133 |
Current CPC
Class: |
A22C 17/004 20130101;
B26B 25/002 20130101; A22B 5/165 20130101 |
Class at
Publication: |
030/276 ;
452/133 |
International
Class: |
A22C 017/12 |
Claims
1. A ring blade comprising a first blade member formed by a
continuous annulus extending about a central axis and having a
cutting edge formed at one axial end for cutting into material with
which said ring blade is brought into contact; and a second member
fixed to said first member for driving the first member rotatably
about the central axis, said second member defining at least a
drive surface by which rotatable drive is imparted to the ring
blade.
2. The ring blade claimed in claim 1 wherein said first blade
member is formed from a thin sheet of material having a
frustoconical section extending between the second member and the
cutting edge.
3. The ring blade claimed in claim 1 wherein said first blade
member is formed from a thin sheet-like member.
4. The ring blade claimed in claim 1 wherein said second member is
formed from molded material.
5. The ring blade claimed in claim 4 wherein said first member
defines structure by which said first and second members are
mechanically locked together.
6. The ring blade claimed in claim 4 wherein second member is
molded in place on said first member.
7. The ring blade claimed in claim 3 wherein said first blade
member is a continuous piece of sheet metal that is cold-formed
into to the annular shape.
8. The ring blade claimed in claim 3 wherein said blade member
defines a radially extending portion spaced from the cutting edge,
said radially extending portion interlocked with said second
member.
9. The ring blade claimed in claim 8 wherein said radially
extending portion defines a plurality of openings into which parts
of the second member extend for interlocking the members.
10. The ring blade claimed in claim 8 wherein said radially
extending portion is defined by an annular axial end face having a
plurality of ridges formed therein.
11. The ring blade claimed in claim 1 wherein said second member
defines a series of gear teeth by which the ring blade is
driven.
12. The ring blade claimed in claim 1 wherein said second member is
formed from a plastic material.
13. The ring blade claimed in claim 1 wherein said second member is
molded in place to said first member and said first member is
formed from a continuous thin sheet metal ring.
14. A method of making a ring blade comprising: a.) forming a
continuous annular blade member having a central axis and opposite
axial ends; b) forming a cutting edge on one axial end of said
blade member; c) placing the blade member in a mold cavity; d)
forming a blade driving member by molding a body of material onto
said blade member so that said body of material and said blade
member are fixed with respect to each other.
15. The method claimed in claim 14 wherein forming said blade
member comprises drawing an annular sheet of metal material to form
a frustoconical section between said cutting edge and the opposite
axial blade end.
16. The method claimed in claim 15 further comprising forming a
radial flange on said blade member an a plurality of holes in said
flange.
Description
FIELD OF THE INVENTION
[0001] The present invention concerns low cost ring blade for use
with a rotary knife.
BACKGROUND ART
[0002] Knives utilizing rotatable ring blades are used in defatting
and removing meat from bones in the meat processing industry. A
typical hand-held rotary knife includes a circular ring blade that
fits within a blade housing. The blade may be rotated by gearing
driven from a flexible shaft attached to the hand held knife. One
such rotary knife is depicted in published PCT patent application
WO 01/24977 A2 which is incorporated herein by reference.
Alternatively, the blade may be gear driven from an air or electric
motor mounted in the knife handle and respectively supplied with
source air through a flexible hose or electric power through a
power cord.
[0003] Ring blades are costly to manufacture and maintain. The
typical blade comprises a thin annular body section that is formed
about a central axis, is frusto-conical and has an annular cutting
edge at one axial end and an enlarged gear forming section at the
opposite end. The blade is machined from a single piece of steel.
The gear forming structure is hobbed to produce axially extending
gear teeth that mesh with a driving pinion gear mounted in the
knife. The blade cost is, in part, due to the relative complexity
of the manufacturing processes required, the high degree of skilled
labor required to produce the blade and the cost of the blade
materials themselves.
SUMMARY OF THE INVENTION
[0004] The present invention concerns a ring blade for use with a
rotary knife. The ring blade comprises a first blade member formed
by a continuous annulus extending about a central axis and having a
cutting edge formed at one axial end for cutting into material with
which the ring blade is brought into contact; and
[0005] a second member fixed to said first member for driving the
first member rotatably about the central axis, said second member
defining at least a drive surface by which rotatable drive is
imparted to the ring blade.
[0006] In accordance with illustrated embodiments of the invention
the driving member is molded onto the blade member during
fabrication of the ring blade. The driving member may be made from
structurally strong polymeric materials, powdered metals, ceramics,
or other appropriate materials or combinations of materials. The
illustrated embodiments of the invention utilize a polymeric
material that is molded in place on the blade member and defines
blade driving gear teeth that project from the ring blade generally
oppositely from the blade edge.
[0007] In some illustrated embodiments the blade member is
fabricated by cold forming a sheet metal ring to produce a desired
configuration. The driver member is then molded in place on the
blade member. The projecting blade end is then sharpened by a
suitable process, such as grinding.
[0008] These and other features of the invention will become better
understood by reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a exploded perspective view of a rotary knife
including a blade housing for supporting a rotary ring blade
constructed according to the invention;
[0010] FIG. 2 is a cross-sectional view of the ring blade shown in
FIG. 1 constructed according to the invention and mounted in and
supported by a blade housing;
[0011] FIG. 3 is a perspective fragmentary view showing part of a
ring blade constructed according to the invention;
[0012] FIG. 4 is a cross-sectional view of another alternative ring
blade disposed in a mold, which is also shown in cross-section,
during the ring blade fabrication;
[0013] FIG. 5 is a cross-sectional view of still another
alternative ring blade constructed according to the invention
mounted in and supported by a blade housing;
[0014] FIG. 6 is a cross-sectional view of the ring blade of FIG. 5
disposed in a mold, which is also shown in cross-section, during
one stage of the ring blade fabrication; and,
[0015] FIG. 7 is a perspective fragmentary view showing part of the
ring blade of FIG. 5.
EXEMPLARY MODES FOR PRACTICING THE INVENTION
[0016] A rotary knife 10 embodying a ring blade constructed
according to invention is illustrated in the drawings. As
illustrated by FIG. 1, the rotary knife 10 comprises a handle
assembly 12, a generally circular, split blade housing 14 supported
by the handle assembly 12, and a ring blade 18 supported by the
blade housing 14 for rotation about a central axis 19. The
illustrated knife is connected to a remote electric motor by a
flexible drive shaft (not shown) that extends into the knife handle
assembly 12 to drive the ring blade via suitable gearing. The motor
and drive shaft may be of any suitable or conventional construction
and are not illustrated. It should be appreciated that other means
may be employed to drive the blade 18. For example, an air motor
may be mounted in the handle assembly 12 and connected to a source
of pressurized air via a suitable hose, or an electric motor may be
mounted in the handle assembly 12 and connected to a power source
by a power cord.
[0017] The handle assembly 12 and blade housing 14 are constructed
as disclosed in PCT application Ser. No. PCT/US00/27488, filed Oct.
5, 2000 the disclosure of which is incorporated herein in its
entirety by this reference to it. Accordingly, the handle assembly
and blade housing are described briefly here.
[0018] The illustrated handle assembly 12 extends away from the
blade 18 and blade housing 14 along a line that is transverse to
the axis 19 allowing a knife operator to wield the knife with one
hand. The handle assembly 12 comprises a handle supporting tubular
frame member 20, a head assembly 24 fixed to the frame member 20. A
removable, ergonomic handle(not shown) surrounds frame member 20
and provides a gripping surface for an operator.
[0019] The frame member 20 is adapted to receive various ergonomic
handles having different configurations to permit an operator to
select a grip which is most comfortable for the operator's hand.
The frame member 20 rigidly supports the head assembly 24 while
providing a channel through which the flexible drive shaft extends
to make a driving connection with the blade driving gearing.
[0020] The illustrated head assembly 24 comprises a head member 40,
a clamp assembly 42 that detachably clamps the blade housing 14 and
the blade 18 to the head member 40, a blade driving pinion gear 27
and a pinion gear supporting bearing 27a. The head assembly 24 also
includes a conventional lubrication system (not shown) by which a
relatively viscous lubricant may be supplied to the pinion gear 27,
the blade 18 and the blade housing 14 via suitable passages.
[0021] The head member 40 positions the blade housing 14 relative
to the handle assembly 12. The illustrated head member 40 is a
generally crescent shaped body that defines a semicircular blade
housing seating region 50, a clamp assembly receiving, socket-like
cavity 52, and a boss 54 that surrounds the frame member 20 and
projects from the head member body opposite to the cavity 52 and
seating region 50. The pinion gear bearing 27a is a tubular member
that is attached to the head member 40 and surrounds a shank of the
pinion gear. The illustrated clamp assembly 42 includes a steeling
mechanism 70 by which the blade 18 is straightened by a knife
operator.
[0022] The clamp assembly 42 firmly maintains the blade housing 14
seated again the seating region 50 to rigidly position the blade 18
while covering the pinion gear 27 which might otherwise be directly
exposed to meat, fat, bone chips, etc. The clamp assembly 42
comprises a clamp body 60 and clamping screws 62a, 62b.
[0023] The ring blade 18 is removed and replaced without the
necessity of removing the blade housing 14 from the head member 40.
The blade housing 14 has first and second end portions 80, 82
extending circumferentially away from opposite sides of the blade
housing split 84 and defines a radially inwardly opening
circumferential groove 86 that receives the blade 18. The blade
housing 14 is split to enable its resilient expansion for removing
and replacing the blade 18 when the clamp assembly 42 is
loosened.
[0024] FIGS. 1-3 illustrate a ring blade 18 constructed according
to the invention that comprises a first blade member 90 and a
second member 92 fixed to the first member 90 for driving the first
member rotatably about the central axis 19. The illustrated blade
member 90 is formed by a continuous annulus having a wedge-shaped
body section 94 extending about the central axis 19 and having a
cutting edge 96 formed at one axial end for cutting into material
with which the ring blade is brought into contact. The member 90 is
formed by machining tubular stock material and appropriately
hardening the material preparatory to grinding the axial blade end
to form the cutting edge 96. The manner of forming the blade member
90 is generally the same as known in the art, i.e., it is machined
from tubular, high carbon, hardenable stainless steel stock, except
that operations related to hobbing gear teeth on the blade member
at the axial end 98 opposite from the edge 96 are not performed.
This results in a much simpler and less costly blade member.
[0025] As shown in the Figures, the member 90 comprises structure
by which the members 90, 92 are fixed together. In the embodiment
of the invention illustrated by FIGS. 1-3 the body section remote
from the blade edge 96 is relatively thick and has a
circumferential groove 102 formed in it that extends radially
inwardly from the outer periphery and a radially extending portion
104 that is knurled to produce a series of radial ridges 106
extending about the blade. The illustrated radially extending
portion 104 is formed by an annular axial end face of the blade
member.
[0026] The driving member 92 defines at least a drive surface by
which rotatable drive is imparted to the ring blade 18. In the ring
blade illustrated by FIGS. 1-3, the member 92 is molded, and
fixedly mounted, on the blade member. The driving member 92 is
formed about the member 90 so that the material forming the driving
member 92 extends into the groove 102 and conforms to the ridged
radially extending portion 104. The conformation of the driving
member with the ridges 106 locks the members 90, 92 against
relative rotation about the central axis 19 while the material in
the groove 102 prevents relative axial movement between the members
90, 92. In this way the members 90, 92 are positively, drivingly
engaged. While a circumferential groove 102 and a coacting knurled
end face 104 have been described as fixing the members 90, 92
together, other suitable structures may be employed.
[0027] The driving member 92 is configured to slidingly fit within
the blade housing 14 and the drive surface is illustrated as
comprising gear teeth 110 that project axially from the blade
member 90 in a direction opposite from the edge 96. These gear
teeth mesh with the pinion gear for driving the blade 18. As best
shown in FIGS. 2 and 3 the driving member 92 defines an axially
extending cylindrical wall 112 along its inner periphery. The gear
teeth 110 are continuous with and project radially outwardly from
the wall 112. The wall 112 functions to strengthen and support the
teeth.
[0028] Although the driving surface on the member 92 is illustrated
as formed by gear teeth, it is to be understood that any suitable
manner of transmitting drive to the blade 18 may be employed.
[0029] FIG. 4 illustrates a step in the fabrication process of a
rotary blade 118 embodying the invention. As illustrated, a blade
member 120 has been placed in the cavity of a mold 122 and material
forming the driving member 124 has been injected into the mold
cavity. The blade member 120 is constructed like the blade member
90 except that the blade body section 126 is machined so that it is
relatively thin and forms a radially inwardly convergent
frustoconical end portion leading to the cutting edge 128. The
remaining structural features of the blade 118 are the same as
those described above with respect to the blade 18 and are
therefore designated by like reference characters.
[0030] As shown in the Figure, the blade 118 is disposed within a
cavity formed by separable mold members 130, 132. The mold members
130,132 are constructed to form an annular closed cavity when the
mold members are closed on the blade member 120. When the mold is
closed, the material forming the blade driving member 124 is
injected into the cavity where it conforms to the blade member and
hardens so that the blade and driving members are secured together.
When the driving member material has hardened the mold members 130,
132 are separated to release the blade 118. The illustrated mold
member 130 is radially split so that after the mold member 132 has
been removed, the split parts of the mold member 130 are separated
to free the blade 118. The illustrated driving member is
constructed like the driving member described above in reference to
FIGS. 1-3 and therefore will not be described further here.
Structural features of the blade driving member 124 are designated
by the same reference characters as those applied to the blade
driving member 92.
[0031] The driving member material in the illustrated embodiments
is a highly engineered resin material such as polyphenyl sulfone,
polyimide, or polyetheretherketone. Although resin materials are
used for the driving member in the illustrated embodiments, other
materials are also possible. For example, the driving member could
be constructed by injection molding a resin loaded with powdered
metal onto the blade member and then heat treating the molded
structure to shrink the member to its final size while driving off
the resin.
[0032] The blade 18 illustrated by FIGS. 1-3 is fabricated like the
blade 118. It should be noted that the hardened blade member may be
ground to produce the cutting edge after the driving member is
molded in place if that is desirable.
[0033] FIGS. 5-7 illustrate another alternatively constructed blade
218 having a blade member 220 formed from a cold-formed sheet of
metal and a driving member 222 that is molded in place on and fixed
to the blade member. The illustrated blade member is formed by
stamping a sheet of hardenable high carbon stainless steel to form
an annulus, and deep drawing the annulus to produce a generally
cylindrical blade body portion 224 projecting axially from a
radially extending flange portion 226 and having a radially
inwardly converging frusto-conical section 228 at its axial end
opposite from the flange 226.
[0034] The blade member 220 comprises structure for fixing the
members 220, 222 together. In the illustrated blade 218, the flange
226 defines an annular array of holes 232 for receiving the
material of the member driving member 222 (See FIG. 7).
[0035] The illustrated blade member 220 is heat treated after being
formed and then the axial end face of the section 228 is ground to
produce an annular cutting edge 230 along its radially inner
periphery.
[0036] Referring to FIG. 6, after the blade member 220 has been
formed it is placed in a mold 240 and material forming the driving
member is injected into the mold. The flange 226 is engulfed by the
material of the member 222 and the driving member material fills
the holes 232 to assure that the blade and driving members are
fixed together.
[0037] The driving member 222 is configured substantially like the
driving members described in reference to FIGS. 1-4 and is not
described further. Likewise, the mold 240 may be constructed as
described previously, or in any suitable manner, and therefore is
not described further. Parts of the driving member 222 and mold 240
that correspond to parts described previously are indicated by
identical reference characters in FIG. 6.
[0038] Although different embodiments of the invention have been
illustrated and described in considerable detail, the invention is
not to be considered limited to the precise constructions
disclosed. Various adaptations, modifications and uses of the
invention may occur to those skilled in the art to which the
invention relates and it is the intention to cover hereby all such
adaptations, modifications and used that fall within the scope or
spirit of the appended claims.
* * * * *